Automatic step turning lathe



I t. 28, 19 8- H. J. SIEKMANN EIAL I 5 v AUTOIATIO STEP TURNING LATHE 3 Sheets-Sheet 1 x-"119d Jan. 27. 1947 s 3 n n w t 53 INVEVNTORS.

mnow .1. SlE/(MANN By 'AIDWILL/AMAKIMSEY ,arronmsrs.

Sept. 28, 1948. q H J. SIEKM-ANN ETAL' 2,450,096

AUTOMATIC s'rnr TURNING LATHE Filed Jan. 27, 1947 I 3 Sheets-Sheet 2 I nvvmrons. HAROLD J. SIEKMANN m. WILLIAM A. xmssr Patented Sept. 28, 1948 AUTOMATIC s'rsr TURNING LATHE Harold J. Sielnnann, Cincinnati, and William A. Kimsey, Mariemont, Ohio. assignors to The R. K. Le Blond Machine Tool Company, Cincinnati, hio, a corporation of Delaware T Application January 21, 1947, Serial No. 724,558

(or 82-14) v 8 Claims.

-ment of work and tool in a lathe to effect theturning automatically of a series of different diameter of work surfaces on awork piece in the lathe. It is still another object of this invention to provide-a step turning lathe in which the headstock transmission provides the drive power for rotating the work, actuating the carriage longitudinally of. the bed, and actuating the cross slide, together with a novel electrical control mechanism for sequentially rendering the carriage and cross slide movements effective in an automatic manner to turn a series of stepped diameters on a work piece in the lathe.

It is still another object of-thls invention to provide a step turning lathe in which no template mechanism is required to effect the turning of any desired number, sequence, and sized steps on a work piece in an automatic manner.

Further features and advantages of this invention'will appear from a detailed description of the drawings in which:

Figure 1 is a front elevation showing a step turning lathe incorporating the features of this invention.

Figure 2 is a plan view of the step turning lathe shown in Figure 1.

Figure 3 is a section on the line 3-3 of Figure 2, particularly showing the magnetic clutch operating mechanism for the carriage and cross slide movements.

Figure 4 isa fragmentary enlarged section on the line 44 of Figure 2 showing the longitudinal movementcontrol limit switch and actuating trip dog bar. I 1

Figure 5 is a fragmentary enlarged view, indicated by the llne'5-5 of Figures 1 and 6 showing the manual longitudinal trip dog mechanism on the lathe apron.

Figure 6 is an enlarged fragmentary front elevation of the lower left-hand portion of the lathe apron, indicated by the line 6-4 of Figure 5.

Figure 7 is a fragmentary enlarged plan view of the cross slide control cam drum mechanism mounted on the ,rear end of the lathe carriage shown in Figure 2.

Figure 8 is an elementary wiring diagram of the control circuits associated with the step turning lathe mechanism.

As illustrative of one adaptation of this invention to a step turning lathe, there is shown a machine having a headstock in which is mounted in a suitable manner on the lathe bed H and which bed also supports a suitable tailstoclr l2. In the headstock Wis the work spindle is having the usual face plate l4 and center it for supporting and driving the work piece at one end while the tailstock center it supports the other end of the work piece W. A suitable main drive motor (not shown) drives the headstock for rotating the work spindle i3 and the work W at the desired cutting speed.

The feed drive power for actuating the cutting tool 'I' at appropriate feed rates relative to the work surface of the work piece W is derived from the transmission mechanism in the headstock it through the output shaft it and the gear ll which drives through a suitable set of change gears l8 and IS the common drive shaft 20 journaled in suitable bearings 2i and 22 in the feed box 23 mounted on the left-hand end of the bed H, as best shown in Figures 1, 2, and 3.

0n the shaft 20 is fixed a drive gear 24 which drives a gear 25 connectable through a magnetic clutch 2 5 to drive a shaft 21 journaled in suitable bearings 28 and 29 in the feed box 23. The carriage feed rod 30 is suitably coupled at 3i to the shaft 21 and extends longitudinally of the bed and is journaled at the right-hand end of the bed in a suitable bearing 32 carried in the block 33 fixed to the bed. Also fixed on the shaft 20 is the gear 34 which drives a gear 35 connectable by a block 33 on the right-hand end of the bed ll.

The lathe carriage 43 is movable longitudinally of the bed on suitable ways 44 and has an apron 45 containing a reversing clutch mechanism 46 which may be continuously driven by the carr-iage feed rod 30 for any position of the carriage and apron along the bed I I in a well known manner. Power is transmitted from the reversing clutch mechanism 46 through suitable gearing 41 and 48 to the rack pinion 49 which operates in a conventional manner with the bed rack SI to actuate the carriage longitudinally of the bed of the lathe. A suitable hand wheel 5| is provided for the manual rapid traversing of the carriage I along the bed. It is also practical to use a power rapid traverse mechanism for actuating the carriage along the bed if desired but this particular mechanism is not shown as it forms no specific part of applicants invention.

There is also provided a reversing clutch mecham 52 carried in the apron l! which is continuously driven by the cross slide feed rod ii for any position of the carriage and apron along the bed ll. Power output from this reversing clutch mechanism 82 is transmitted through suitable gearing 53. II, and II to the cross feed screw it suitably journaied against axial movement in the carriage 43. A cross slide hand wheel 51 is provided for manual actuation of the cross slide ll of the lathe operating through suitable nut and screw mechanism (not shown) in a well known manner.

Thus, with the headstock ill operating and power being applied thus to the shaft 20 of the feed box 23, energizing the magnetic clutch 2| will cause the carriage to feed along the bed, its direction being determined by the appropriate setting of the reversing clutch mechanism It. Likewise, when the magnetic clutch 36 is energized, power will be applied to actuate the cross slide in the desired in or out direction, depending upon the setting of the reversing clutch mechanism 52. The rate of feed may be determined by selecting the proper change gears II, It, and i2 and by varying the change gears 84 to get the desired cross slide feed rate independently of the carriage feeds. Rapid traverse mechanism may also be applied to the cross slide in addition to the manual hand wheel actuation by the hand wheel 51, if desired.

In conjunction with the longitudinal movement of the carriage, there is provided a trip dog mechanism for automatically determining the exact shoulder positions or points of stopping of the carriage travel and starting of the cross slide movement in and out radially of the work piece. This mechanism comprises a floatingly mounted dog bar ll supported slidingiy at itsright-hand end in a suitable bearing il in the block 32 while its other end is connected by suitable screws II to a detent plunger 82 fioatingly mounted for axial movement in bearings 02 and 24 carried in the feed box 22 Intermediate of the detent shaft 62 is formed a detent groove 05 in which operates the 'detent ball I urged toward the groove I by a suitable compression spring I! operating against a switch plunger 82 having an enlarged head 8! contacting the ball 06. The outer end of the detent plunger 08 engages a micro limit switch It fixed to the feed box 22. Centering springs II and I2 engaging the abutment surfaces 13 of the feed box and engaging against abutment collar 14 behind the bearing members 62 and 64 serve to normally move the detent shaft 22 and the dog bar It to a centralized position, as shown in Figure 4, in which position the limit switch Ill having its contacts Ila normally closed and its contacts 'llb normally open. Deflection of the dog bar it in either direction actuates the limit switch I. so as to reverse this condition, namely, open contact Ila and close contact lilb.

A series of adjustable dogs ll corresponding to the steps I. on the work piece are engaged by an actuating dog 11, best seen in Figures 1, 5, and 8. This dog 11 is fixed ,to a rock shaft 12 suitably journaled against axial movement in the apron II, the inner end of the rock shaft being connected through a lever arm I! with a solenoid 2| carried on a suitable plate Ii fixed to the apron 45. Energizing the solenoid It causes the dog to swing counterclockwise. Figure 5, outwardly to release its end "a from engagement with any of the trip dogs II so that the carriage may move without actuating the dog bar '0. When the solenoid II is de-energized. however, the dog Il drops back by gravity to the position shown in Figure 5 so that it may engage any one of the trip dogs 15 on the dog bar I! and move the do bar axially to actuate the limit switch ll, Figure 4, as described. A manual control handle .2 is journaled on the rock shaft 18 and has a pin 23 adapted to engage around the back of the trip dog 11 so that when the lever is pulled upwardly. it will manually lift the dog 'll out of operative position with the trip dog IS on the bar II. when the handle is released, it will drop back by gravity to the position shown in Figures 5 and 6 with the pin 23 engaging a stop pin 24 carried in the apron II.

The cross slide movements are automatically controlled by means of a cam drum ll, best shown in Figures 2 and 'l, joumaled by its shaft It in a suitable bracket ll fixed to the rear of the carriage II by suitable screws 28. Fixed to the shaft 2! is a worm wheel 22 which is engaged and driven by a suitable thread ll formed on the cross feed screw 5'. A series of adjustable trip dogs 8| are provided on the periphery of the cam drum l! which engage a series of limit switches 02 through 90, inclusive, corresponding to the various steps I. on the work piece W. Thus, as the cross slide I2 isfed inwardly or outwardly, the cam drum 25 rotates and sequentially presents the various trip dogs It to the limit switches 22 to 22 for progressively inciting cross slidemovement at predetermined timed relationships with the relative in and out position oi. the cross slide. The operation of the machine is performed by electrical apparatus best shown in Figure 8. The

current supply for operating the control apparatus may be received from suitably alternating current supply leads I" and ill connected to the primary windings I02 and illof a transformer having a secondary winding I through suitable fuses ill and I" to the leads I" and I, respectively.

with the headstock being appropriately driven and rotating the work piece W and the drive shaft 22 in the feed box 23 operating as described in conjunction with the operation of the headstock it, the tool feed movement is started by pressing the feed start button lill which energizes the relay lit to close contact Illa which looks in the relay ill. Energizing relay Ii. also closes contact H2 to complete a circuit to the rectifier H2 which then supplies direct current through the leads H4 and H5 for the magnetic clutches 28 and 20. Energizing relay III also closes contact H6 connecting lead ill with lead I". When this is done, contact l2la actuated by armature i2lb is also closed by the energizing of relay I20.

A selector switch ill, preferably mounted on the front of the apron and carriage, as shown in Figure 1, has a neutral disconnected or hand position where it may be located when it is desired to adjust the tool by manual manipulation of the hand wheels 5i and 51 without the autmatic control apparatus functioning. The machine may be operated in a semi-automatic condition in which only the longitudinal feed of the carriage is controlled automatically and the in and out motion or adjustment of the cross slide and tool is effected manually. To set the control mechaconnected a him for this type of operation, the selector switch H is operated so as to move its contact Illa to interconnect lead I01 with lead I I8. With contact II8a closed and the start button I08 depressed to energize relay IIO, as described, the relay I20 is energized by closing of contact I20a. Energizing relay I20 closes contacts I2! and I22 supplying power to the magnetic clutches 26 and 35 and opens contact I23 to tie-energize the latch solenoid 80 and allow the trip dog TI to drop into operative position with relation to the trip dog 15 on the dog bar 59, Fi ure'5. Under these conditions, the relay I24 is de-energized dropping armature I24a so that its, contact "I25 is closed while its contact I26 is open so that only the carriage actuatin magnetic clutch 20 is energized which starts the longitudinal feed movement of the lathe carriage.

This longitudinal movement of the carriage continues until the dog Tl engages one of the dogs 15 on the dog bar 59 and shifts the dog bar 59 so as to actuate the limit switch which opens contact 10a. Closing contact 10b energizes relay I24 so as to open contact I25 to deenergize the magnetic clutch 26 to stop further motion of the carriage. Contact I26 is closed and contact I21 is closed but since contact I23 is open due to relay I20 being energized, the solenoid 80 is not operated to lift the latch trip dog I1 so that the dog bar 59 remains actuated to operate the limit switch I0.

Under these conditions, the cross, slide may be adjusted manually by manipulating the hand wheel 51 to adjust the cuttingtool relative to the work for the next diameter surface to be turned. After having thus adjusted the cross slide, a longitudinal movement may again be resumed by lifting the control handle 82, Figures 5 and 6, to release the dog 11 from one of the trip dogs on the bar 59 so as to allow the bar-to shift back to its centralized neutral position to release the limit switch 10 which causes contact 10a to close and causes contact 1022 to open. Opening of contact 10b de-energizes relay I24, closing contact I25 to again energize the carriage control magnetic clutch 26 and start up the longitudinal feed movement again. This process may be continuedfor each of the respective steps 16 it is desired to cut on the work piece by appropriately setting the dogs I5 in proper relationship to the spacing desired on the work along the bar 50 and continuing the repetition of the cycle, tripping the longitudinal movement each time after manually setting the cross feed movement by lifting the control lever 82.

Both the carriage and cross slide may be operated to perform a predetermined automatic cycle for step turning the work piece W. When both the carriage and cross slide are to be controlled automatically, the selector switch 8 is moved so that its contact 8b is closed, interconnecting lead I01 with lead l20. Under these conditions, the relay I29 is energized actuating armature 828a, closing contact I30 associated with the cross slide magnetic clutch 36. Contact 13! is also closed upon energizing of relay E29. Relay I24, however, remains 'de-energized because contact 10b is open so that the contact I25 remains closed to apply power to the carriage magnetic clutch 28 to effect the carriage movement longitudinally of the work.

Closing of contact l3I energizes relay I to close contacts [2011, HI, and I22 in the supply leads to the magnetic clutches and 36. Energizing relay l20 opens contact I23 and closes 6 locking contact I20a to hold the relay I20 in cit cuit around the contact 10a of the limit switch II.

Longitudinal movement of the carriage'continues until the trip dog TI engages the next dog I5 on the dog bar 50 to again actuate the limit switch Ill, so as to open contact 1011 and close contact 1017. Closing of contact 10b energizes relay I24, opening contact I25 to de-energize the carriage feed magnetic clutch to stop the carriage movement and closes contact I20 in the circuit to the cross slide magnetic clutch 38 and also closes contact i2'l.

The cross slide movement is thus initiated and continues until a trip dog BI on the cam drum 85 operable by the rotation of the cross feed screw during the cross slide movement engages a limit switch such as the limit switch 92 whereupon the relay I32 is energizedactuating armature I32a,

closing contact I33 in the supply line to the cross feed magnetic clutch opens contact I34 to deenergize relay I20 which opens contacts I2I and I22 and closes contact I23 and opens contact I20a.

- Energizing of the relay I32 also opens contact I35 so that the solenoid 30 is tie-energized and the dog l1 remains in its lowered position to engage a dog 15 on the dog bar 59. Y

Under these conditions, the limit switch is so actuated that its contact 201) remains closed to energize the relay I24 to close contact I21, to open contact I25 and close contact I26. Further movement of the cross slide relieves the dog M from limit switch 92 so that relay I32 is again deenergized, closing contact I35 with the result that the solenoid is energized to raise the dog TI and control handle 82 to allow the dog bar 59 to neutralize itself again sons to operate the limit switch 10 to close contact 10a and open contact 102) which again institutes the carriage movement in a longitudinal movement after having automatically repositioned the cross slide. The next step portion of the work piece is then turned until the dog 11 again hits a dog 15 on the bar 59 to again institute cross slide movement as described. This cycle of operation is repeated until all of the various step portions of the work piece-W are completed automatically, there being a series of limit switches 92, 93, 94, 95, 96, 97, 08, and 99 and corresponding trip dogs 9I to efifect'the stopping of the cross slide movement and the automatic institution of the longitudinal carriage movement after the cross slide has been positioned to the proper diameter of the work surface for each step to be cut.

Normally closed safety limit switches I36 and I3! are engaged by the leftward and rightward movement of the carriage, respectively, mounted on the bed of the machine serve to automatically de-energize the relay III! so as to open contacts HI, H2, and IIS to de-energize theautomatic control circuit and to prevent any false operation of the machine when the carriage is moved to the extreme edge of the lathe bed or to any intermediate restricted positions depending upon the setting of the limit switches I36 and I3! along the bed. These switches are utilized to stop the cycle at the end of the machining operation in either direction of travel.

The entire machine may be stopped at any time by depressing the stop button I38 so as to similarly de-energize the relay H0 with the same results of cutting out the control circuits by opening contacts I, H2, and H6.

There has been provided a transmission and control mechanism for automatically regulating the tool movement in a step turning lathe in .which the headstock transmission furnishes th aasaooe tuating the cross slide in radial in or out feed movements. and in which there is provided an electrical control system for automatically sequentially controlling the carriage and cross slide movements in a predetermined cycle of operation for eflectlng automatically a series oi step turning operations on a work piece in the lathe.

While the apparatu herein disclosed and described constitutes a preferred form of the invention, it is to be understood that the apparatus is capable of mechanical alteration without departing from the spirit of the invention and that such mechanical arrangements and commercial adaptations as fall within the scope of the appendant claims are intended to be included herein.

Having thus fully set forth and described this invention, what is claimed as new and desired to be-secured by United States Letters Patent is:

i. In a step turning lathe having a headstock. a work spindle in said headstock including means for supporting and rotating a work piece in said lathe, a feed drive transmission actuated by said headstock. a pair of magnetic clutches driven from said feed transmission, a cariage feed rod journaled longitudinally of the bed of said lathe connectable or disconnectable to be driven from said feed transmission by one of said magnetic clutches. a cross slide feed rod iournaled longitudinally of the front of said bed of said lathe adapted to be connected or disconected through the other of said magnetic clutches to said feed transmission, reversing mechanisms in said apron operably connected to be driven from said feed rods for any position of relative movement of the apron and carriage of said lathe on said bed, means for connecting power from one of said reversing mechanisms associated with the carriage feed screw to actuate the rack pinion in the apron of said lathe to effect longitudinal feeding movements of the carriage along the bed, and further gear transmission means connecting said other reverser mechanism associated with the cross slide feed rod to the cross feed screw of said lathe for eflecting transverse movements of the cross slide, and electrical control mechanism operated by the relative movement of the carriage and cross slide for energizing and de-energizing said magnetic clutches in a predetermined sequential order to effect a step turning operation of a cutting tool on the cross slide of said lathe on a work piece mounted on the work spindle.

2. In a step turning lathe having a headstock and a tailstock .ior supporting and rotating a work piece in said lathe, a feed box on the bed of said lathe including a common drive shaft and a pair oi magnetic clutches driven therefrom, a feed power transmission from said headstock to said common drive shaft. a carriage feed rod extending longitudinally the front of the bed connected to be actuated through one of said magnetic clutches, a cross slide teed rod mount,- ed longitudinally the front'oi the bed adapted to'be connected or disconnected from said common drive shaft by the other of said magnetic clutches, and electrical control means for sequentiallyoperating said magnetic clutches ineluding. a limit switch in said feed box, a lon- 8 apron of said lathe for actuating said dog bar to control the operation of said limit switch in the feed box, and further electrical control means comprising a cam drum rotatably mounted on the carriage and actuable by the rotation of the cross feed 'screw including a series of trip dogs on said cam drum and a series of limit switches actuable by said trip dogs and electrical control relay means actuable by said limit switch in the feed box and the limit switches on said carriage for effecting a step turning operation or a cutting tool on a work piece in said lathe.

3. In a step turning lathe having a carriage and a cross slide. electrical control means for sequentially effecting the operation of said carriage or cross slide to perform a step turning operation including magnetic clutch means ior applying power from the headstock of said lathe to actuate the carriage or cross slide movements, a limit switch actuable by the carriage movement along the bed for arresting the carriage movement by operating electrical control mechanism to de-energize said magnetic clutch means for eflecting carriage movement, further electrical control means comprising a cam drum having a series of trip dogs and limit switches associated with said trip dogs actuable by the rotation of the cross feed screw for arresting cross slide movement at predetermined radial positions relative to the work axis, and electric selector switch means to cause said lathe to operate with the control of the limit switch confined to carriage movement while said cross slide control cam drum mechanism is inoperative, said selector means being adjustable to another position whereby both the carriage actuated and cross feed screw actuated electrical control mechanism operates jointly to automatically eifect a step turning movement for the cutting tool of the lathe.

f 4. In a step turning lathe having a carriage and a cross slide, electrical control means for sequentially effecting the operation of said carriage or cross slide to perform a step turning operation including magnetic clutch means for applying power from the headstock of said lathe to actuate the carriage or cross slide movements. a limit switch actuable by the carriage movement along the bed' for arresting the carriage movement by operating electrical control mechanism to de-energize said magnetic clutch means for eiiecting carriage movement, further electrical control means comprising a cam drum having a series of trip dogs and limit switches associated,

with said trip dogs actuable by the rotation of the cross feed screw for arresting cross slide movement at predetermined radial positions rela tive to the work axis, and electric selector switch means to cause said lathe to Operate with the control oi the limit switch confined to carriage movement while said cross slide control cam drum mechanism is inoperative; said selector means being adjustable to another position whereby both the carriage actuated and cross feed screw actuated electrical control mechanism operates Jointly to automatically eflect a step turning movement for the cutting tool of the lathe, said selector switch means having a hand position whereby both of said electrical control mechanisms actuable by the cross feed screw are rendered inoperative for manual manipulation of the carriage and cross slide movements.

5. In an electrical control mechanism for a step turning lathe, a magnetic clutch for applyhis power to actuate the carriage in longitudinal movement, a second magnetic clutch controlling the application of power to the cross slide of the lathe, a limit switch actuable by the movement of the carriage to predetermined positions for deenergizing the magnetic clutch applying power .cam drum Journaled on said carriage and driven in timed relationship with the movement of the cross slide, and control means operable by the rotation of the cam drum to arrest cross slide movement upon movement of the cross slide to predetermined in and out positions, and selector switch control means forrendering one or both of the control means for the carriage or cross slide movements effective or ineifective.

6. In an electrical control system for a step turning lathe having a carriage, a cross slide on the carriage, means for driving said carriage and cross slide from the headstock including a magnetic clutch for applying power for carriage movement, a second magnetic clutch for applying power for cross slide movement. electrical control devices including a limit switch actuable by the carriage movement to predetermined positions for tie-energizing the magnetic clutch for carriage feed movement. amanually operated releasing device operable to re-energize said magnetic clutch for carriage movement, a drum cam mechanism including .a series of limit switches carried on the carriage of said lathe actuable by cross slide movement to predetermined positions for stopping cross slide movement by deenergizlng the magnetic clutch for applying power to the cross slide. said electrical control system including further mechanism operable in conjunction with said magnetic clutch means to automatically stop the cross slide movement and institute the longitudinal feed movement of the carriage by electrically actuating the manually controlled trip member. I a

7. In a step turning lathe having a headstock and a tailstock for supporting and rotating a work piece. a feed box including a pair 01 magnetic clutches driven from the head stock transmission, electrical control means for energizing said magnetic clutch devices for actuating the carriage and cross slide including a manuallyand electrically actuated trip dog carried by the apron and engaging trip dogs on a dog bar shiftable to actuate a limit switch in said feed box for deenergizing and energizing the magnetic clutch for applying power to the carriage, a cam drum switch actuating device including a series of limit switches actuable sequentially upon movement of the cross slide to predetermined in and out positions for stopping cross slide movement and rendering said electric power actuated trip mechanism operative to again institute carriage movement, and means operable by said trip member on the apron for instituting cross slide movement when the carriage movement is stopped.

8. In a step turning lathe having a headstock and a tailstock for supporting and rotating 9. work piece, a feed box including a pair of magnetic clutches driven from the headstock transmission, control means for energizing said magnetic clutch devices for actuating the carriage and cross slide including a manually and electrically actuated trip dog carried by the apron and engaging trip dogs on a clog bar shiftable to'actuate a limit switch in said feed box for de-energizing and energizing the magnetic clutch for applying power to the carriage, a cam drum switch actuating device including a series of limit switches actuable sequentially upon movement of the cross slide to predetermined in and out positions for stopping cross slide movement and rendering said electric power actuated trip mechanism operative to again institute carriage Number movement, and means operable by said trip member on the apron for instituting cross slide movement when the carriage movement is stopped, and selector switch means for rendering either the carriage control trip mechanism operative alone or both said carriage trip mechanism and the cross slide cam drum trip mechanism operative simultaneously.

' HAROLD J. SIEKMANN.

WILLIAM A. KIMSEY.

REFERENCES crran The following references are of record in the file of this patent:

UNITED STATES PATENTS FOREIGN PATENTS Country Date Germany Nov. 5,

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